UPDATE: Fire marshal: Gas leak caused NJ apartment blast

HADDON HEIGHTS (AP)  Authorities say natural gas leaking from an appliance caused an accidental explosion that blew off the top two floors of a southern New Jersey apartment building and left two women hospitalized.

Camden County Fire Marshal Paul Sandrock says the leak occurred Saturday afternoon in a second-floor unit in the Haddon Heights building, but didnt specify the appliance. Gas accumulated on the third floor, and the explosion and subsequent fire occurred when the second-floor tenant started her stove.

Authorities say the woman suffered critical burns, while another woman was treated for minor injuries.

Witnesses who live nearby said the blast shook their homes and the fire quickly destroyed the building. The building remained cordoned off Sunday as crews worked to clear the site and investigators continued to sort through the rubble.